Pneumatic caisson.



illil lw I PATENTBD AUG. 11, 1908. o. c. EDWARDS, J1. v PNEUMATIC GAISSON.

APPLICATION FILED APP-.30, 196- III No. 395,543. PATBM AUG. 11, 1903.

0. c. BDWARDS, J1.

PNEUMATIC GAISSON.

nruquloli Plum APR. 30, 1900.

3 SHEETS-SHEET I.

Eat;

' PATNTED AUG. 11 .1908. '0. c EDWARDS, .11. T

PNEUMATIC czussou.

APPLICATIO! TILED APR. 30, 1906- a auxin-aunt a wanna:

- ing in the direction indieated b UNI ED STATES PATENT OLIVER CROMWELL EDWARDS, JR., OF TROY, NEW YORK.

PNEUMATIC carsson.

Application filed April so, me. Serial No. s14,s4s.-

To all whom it may concern:

Be it known that I, Omvrm C. EDWARDS, Jr., a citizen of the United States, residing at Troy, in the county of Renssclaer and State of New York, have invented certain new and useful Imprm'ements in Pneumatic Caissons and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to improvements in pneumatic caissons, and more particularly to caissons cast of concrete.

Among the objects in view is the production of a caisson of minimum ex onse, and of maximum strength and durabi ity and susceptible of being constructed and transported with facility.

With this and further objects in view the invention comprises certain novel constructions, combinations and arrangement of parts, as will be hereinafter fully described and claimed.

In the accompanying dra\\-'ing:-1 igure l is a top plan view of a caisson incorporating one embodiment of the present invention, a cotfer-dam being indicated as superimposed on the caisson proper, and the air and spoil shafts being omitted. Fig. 2 is a longitudinal, vertical. central section, taken on the plane of line 22 of Fig. 1. Fig. 3 is a transverse, vertical section, taken on the plane of line 33 of Fig. 1, and also of Fig. 2, and looking in the direction indicated by the arrow. Fig.3 is a similar section taken on the plane of line 44 of Fig. 1, and also of Fig. 2. Fig. 5 is a longitudinal, vertical section, taken on the plane of line 5-5 of Fig. 1. Fig. 6 is an enlarged detail transverse, vertical section through the air shaft and surrounding parts. Fig. 7 is a top plan view of a fragment of a modified form of caisson. Fig. 8 is a top plan view of a slightly modified form of caisson in which the vertical studs and diagonal braces of the trusses are incorporat d in a continuous wall. Fig. 9 is a lon itudinal, vertical, central section through the same. Fig. 10 is a transverse, vertical section taken on the plane of line 10-10 of Fig. 8, and also of Fi 9, and lookv the arrow. Fig. 11 is a similar section taken on the lane of line 1111 of Fig. 8, and also of Fig. 9. Fig. 12 is an outline illustration of a and also of Fig. 19.

series of eaissons disposed for constitutinga Patented Aug. 11, 1008.

bed for a subaqueo'us tunnel, the cofi'er-dam wall being indicated in position. Fi 13 is a transverse section taken on the pl ane of line 1313 of Fig. 12. Fig. 14 is a top plan view of a further modification in which the diagonal braces of the trusses are omitted. Fig. 15 is a' longitudinal, vertical, central section of the parts seen in Fi 14. Fig. 16 is a transverse, vertical centra section of the parts seen in Fig. 14. Fig. 17 is a longitudinal, vertical section taken on the plane of line 17-17 of Fig. 14, the air and S)O II shafts being omitted. Fig. 18 is a top view of a further embodiment of the present} invention. Fig. 19 is a longitudinal, vertical, section, taken on the plane of line 19-19 of Fig. 18. Fig. 20 is a similar section of the same taken on the plane of line 2020 of Fig. 18, the parts being shown on an enlar ed scale. Fig. 21 is a transverse section, taicen' on the plane of line 2121 of Fi 18, and also of Fig. 19. Fig. 22 is a similar section taken on the plane of line 2222 of Fig. 18, Fi s. 23, 24, 25 and 26 are transverse sections through caissons embodying the present invention in slightlymodified forms.

As above intimated one of the essential objects of the present invention is the obtaining of a maximum capacity for resistin strains, and largely eliminatm the item 0 expense, and, in carrying out this and other ob ects, I ma? incorporate the invention in any one of tie several embodiments illustrated in the accompanying drawing, all of which disclose the same general conception incorporating the em loymentof a truss formation for bracing t 1e walls and roof of. the caisson for strengthening the same to resist strains.

In the embodiment illustrated in Figs. 1 to 5 inclusive, I employ a casing consistin of side walls l1, and end walls 2-2, pre erably cast integral from concrete, suitable steel or iron stiffening bars or rods being embedded in the concrete. It is to be observed that in the construction of the caisson all of the parts are strengthened by embedded steel members. The lower edge of the side and end walls may be beveled, as illustrated, for. producing a cutting edge, and the u per edges of said walls are connected by a orizontal, flat roof '5 which is cast integral with the walls. Beneath the roof 5 are arranged o transverse bra formed inte ral with thesiot. v connected with the roof 5 1 the transverse braces S,

' is the customary cofferdam structure 11,"

by vertical studs 7-7. If

desired, longitudmal braces may be rovided similar to t ie transverse braces bein sufficicr. ordinarily, but the longitudinal braces bein employed in conjunction with exceptional ly large caissons. It is to be noted that eaclrof the braces 6 constitutes a lower cho'rd, while the'material of the roof 5 constitutes the upper chord of a truss, the chords bein spaced by the studding 7. By preference the lower end of each of the studs 7 is flared at the point of connection with the brace 6. In other words, the vertical studs are referably provided with inc-line fillings at it ie point of juncture with the respective brace 6. The working chamber produced b Y the upright walls 1 and 2 and the roof 5 is further strengthened by suitable knee-braces 8-8 formed integral with and connecting the respective side and .end walls with the roof at the point of juncture of the roof with the wall. ach of the knee-braces 8 is provided at each side with a filling 9' for the trihedral an le formed b Y the intersection of the knee-brace with tie vertical wall and roof of the working chamber. Each kneebrace with its filling thus constitute a powerful factor in resisting twisting strains, and also resisting inward crushing strains. At each corner of the workin chamber, formed by the juncture of the em s, sides and roof is arranged a filling 10 for the trihedral angle formed by the intersection of the vertical walls and roof of the working chamber.

Mounted upon the caisson roof and extending as far above the same as is necessary which may be formed of wood, or concrete, or other material as preferred. The cofferdam structure is braced by longitudinal parallel beams 12-12 and transverse arallel beams 12-12'. In addition to the n'acing action of the beams, said beams have the further function of stiffening and strengthening the roof 5 andaiding in sustaining the same, and transmittin strain therefrom to the sides and ends 0 the caisson. Forthe purpose of insuring the transmission of strains, each of the beams 12, as clearly seen in Fig. 5, is connected at its ends by vertical posts 13 to the roof and end wall of the caisson. Intermediate the length of each beam 12 are arranged incline braces 14-14 which connectthe drawing, of course as man rods may be e the requisite 20-2-0, embedded respectivclyin the incline braces and in the vertical studs. Each of the transverse beams 12 is constructed as.

nearly like each of the lon itudinal beams 12 as is conveniently possi le. Each. of the beams 12' is formed integral with each of the beams 12 at the point of intersection, such point of intersection occurring in vertical alinement with one of the vertical studs 7 A tie rod 22 preferably extends longitudinally of the vertical column 23 formed at the juncture of each of the transverse beams 12' with the-longitudinal beams 12, said tie rod extending through the roof 5 and longitudinally through the respective vertical stud 7, and through the brace 6. Each transverse beam 12 is provided with incline braces 24-24 intermediate its length and "erlical studs 25-25 at its ends connecting the respective beams 12 with roof 5, and preferablv cast integral with both said beam and roof. Thus it is to be observed that with a comparatively small uantity of concrete and metal bars or rods, I have been able to produce a structure susceptible of resisting inward crushing strains, and also of-resisting twistingstrains due to racking of the caisson during operation. The beams 12 and 12' constitute upper chords of trusses of which the roof 5 constitutes the lower chord, the chords being connected by suitable incline braces and vertical studs. The truss formations make possible the securin of the maximum strength and rigidity wit a relatively small quantity of material. It is to be observed that I have, for the purpose of clea-rness, omitted from Figs. 1,2 and 4 the showing of the man and spoil shafts, and have only indicated therein the apertures 26-26 formed in the roof 5 for the rece tion of such shafts. However, in Fig.

6, I iave illustrated in detail a form of connection between each of the shafts and the that the shaft 27 rests u on a plate 2S which is of circular shape and formed angular in transverse section, being preferably a right angle bar. Upon the plate 28, inside the shaft 27,- is arranged a ring :29 of angle material which is suitabl bolted or otherwise secured to the plate 28, the ring 29 in turn being riveted, or bolted, or otherwise suitably secured to the shaft 27. the retention of the parts in their proper posi tion, I )referably provide bolts 36-30 which are leaded at their free ends and bent roof 5. Referring to Fig. 6 it will be seen v In order to insure so as to-be embedded well into the material of the roof 5, and beyond their bent portions, said bolts 30, extend upwardly throu h the plate 28 amhringZQ, and are )rovide with suitable ni tstfor retaining sai plate firmly in sitiun.\\

n Fig. 6 Ihavc illustrated a. broken away portion of concrete filling upon the roof which filling is placed for the urpose of adding weight afteroperations have begun for insuring the sinking of the caisson.

In Figs. 8 tell inclusive I have illustrated a modified embodiment of the invention in which I produce the. truss formation by the use of continuous relatively thin walls'or webs as substitutes for thevertical and inclined braces. In these figures, I have shown a working chamber made up of side walls 31', end walls 32, and a roof 33. The roof is braced with respect to the side walls b knee-braces 3434 suitably spaced apart. Tliese knee-braces may, of course, be provided with fillings corresponding to fillings 9 if desired, but such fillings are not illustrated in the drawing. The trihedral angle produced bv the union of the side and end walls and roof is provided with a filling 35 prefer abl made up of knee-braces cast integral with the side and end walls and roof and constructed of polyhedral angle formation. The working chamber is further braced by transverse braces 36-36 cast inte ral with the side walls and connected with t 1e roof by integral continuous webs 37. Above the roof 33 are provided longitudinal arallel beams 383S andtransverse arallel cams 39-39 each of said beams eing formed integral with a continuous web 40*40, which in turn is formed integral with the roof 33. The beams 38 and 39, at their points of intersection are preferably connected with the braces 36 b vertical tie rods 4141. Thus it is to be 0 served that the structure seen in Figs. 8 to 11 inclusive corresponds to the structure first described but difl'ers therefrom only in that continuous webs are emploved instead of the open work produced by inclined and vertical braces.

A further embodiment of the present invention is illustrated in Figs. 14 to 17 inclusive. The structure seen .in these figures involves a working chamber in ade up of side walls 42 and end walls 43 cast integral, and also formed integral with the horizontal roof 44', the roof being preferably constructed with knee-braces extending continuously of the contacting edges of the roof and the vertical walls. It is to be noted that in the foregoing embodiments the beams or chord members are connected with the roof at their ends by vertical studs, but such structure, while preferred, need not be employed for embodying the essential conception of the present invention as will be seen from Figs.

14 to 17 inclusive, in which suitable transverse braces 44.44 are arranged in the working, chamber and suitable longitudinal braces 45-45 are'also arranged therein, all of said braces extending to and being formed integral with the vertical walls of the working chamber. In the braces 45 will be seen the embodiment of the longitudinal braces above suggested as adapted to be employed in conjunction with the structure seen in Fig. 5, if desired. Of course, the amount of strain to which the caisson is to be subjected and its size will largely govern as to whether or not the longitudinal braces 45 will be employed' At the points of intersection of the races 44 and 45 are arranged vertical studs 4646 which are formed integral with the intersecting braces and which are extended to and formed integral with the roof 44 The side and end walls of the caisson extend upwardly above the roof 44 and suitable longitudinal, parallel beams 47-47 connect the end wells, and similar transverse beams v 84S connect the side walls of the caisson a ove the roof 44'. The beams 47 and 48 are, of course, preferably cast integral with 'the\ side and end walls. At the points of intersection of the beams 47 and 48, which points, are in vertical alinement with the points of intersection of the braces 44 and 45, the said beams are connected b vertical studs 4S'48' t0v the roof 44. vertical tie rod 49 ext-ends longitudinally throu h each of the vertical studs 48 through tie roof 44', and through the corresponding stud 46, the tie rod projecting beyond the res ective beams 47 and 4S and braces 44 an 45, and being suitably connected therewith. Suitable tie rods longitudinally disposed with respect to the roof and beams or braces ma also be employed as indicated in'Fig. 17 an any other metal bars or rods may be embedded in the concrete as may be found desirable for adding to the strength of the structure. When the span between the studs 43'," or between either of the studs 48' and the side or end wall of the casing is of sufficient length to make it desirable to have further bracing, I propose to employ additional studs 4S"48", and when the span between the studs 46, or between either of the said studs and either of the walls of the casing is sufficiently great to make desirable additional bracing, I preferably employ suitable studs 46'--46f within the workm chantber corresponding to and in vertica alinement with vertical studs 48 above the roof of the working chamber. A suitable tie rod 49' is preferably provided for each set of studs 48" and 46 and extends longitudinally therethrough and throu h the roof for connecting the beams 47 and 48 with the corresponding braces 44 or 45.

.For the sake of convenience of description, attention is directed to Fig. 7 which discloses a top plan view of a fragment of a structure corresponding to that seen in Figs. 14 M17 inclusive, with the exception that the walls 43' of the casing are of such area as to produce a square caisson. Therefore, the beams 47 and cross beams same length, and the span between one beam and another is the same as between an other two beams. Therefore, when sucli smn is of sufficient size as to require more than ordinary bracing, I provide the studs 48), indicated in dotted line in Fig. 7. Of course, the trusses of the working chamber of the structure shown in Fig. 7 may, if desired, be correspondingly braced. The show-- ing in Fig. 7 is incorporated in this applicacation, particularly for bringing out t 1e fact that the present nnproved caisson may be constructed of any size or shape, and requires only such slight variations in the form of truss employed as are adapted for producing the structure of truss best designed for carrying the strains to which the same may be subjected.

In Figs. 18 to 20 inclusive, I have illustrated an embodiment of caisson which incorporates mostof the details embodied in the several different modified forms above set forth, and, therefore, for the purpose of consideration of the specific claims hereinafter presented, the showing in Figs. 18 to 20 inclusive may be accepted as preferred in this appli cation. The structure illustrated in the said Figs. 18 to 20 inclusive, involves a casing consisting of side walls 5252, and endwalls 5353, preferably formed ofconcrete and east integral, suitable steel oriron stiffeningbars or rods bein embedded in the concrete. The upper end of the casing formed of the side and end walls 52 and 53 is closed by a hori zontal, integral, concrete cast roof 54. The roof and sides thus constitute a working chamber within which are arranged lon itudinal beams 55, constituting the lower chords of trusses, the said beams 55 extend ing throughout. the length of the caisson-and eing cast at their ends integral with the vertical walls. Immediately above the beams 55 are longitudinal beams 56-56, which are formed integral with the roof 54 throughout their length, and at their ends are formed integral with the vertical walls. The beams 55 and 56 are connected at various points intermediate their length by vertical studs 57-57 and 57'-57', and between each two of the vertical studs is disclosed an incline brace 58 which connects the two beams 55 and 56. The open work truss is thus produced, the beam 56 serving as the upper chord and the beam 55 as the lower. Arranged transversely of the working chamber are beams 5959, which intersect the beams 55 and are formed integral therewith at the points of intersection, the ends of the beams 59 being formed integral with the sidewalls 52. Immediately above each of the beams 48 are of the 59 is a corresponding beam 60, which is formed integral throughou: its length with the roof 54, and at the ends is formed integral with the walls 52. .b seen clearly in Fig. 22, the beams 59 and (.4- are connected by incline braces (ll-61, as well as by the vertical studs 57,'which occur at the points of intersection of the beams 5'." and 60 with the beams 52 and 56. Other bracing members may be employed for connecting the beams 59 and 60 as are found desirable. Thus it is to be seen that I provide trusses extending both longitudinally and transversel within the working chamber, and the sai trusses may, of course, as abovc'injicated, be constructed with a greater or less number of connecting members as preferred, or-when desirablc the connection between the chords of the truss may be made in the form of a continuous web as hereinafter set forth. Above. the roof are arranged trus members corre- 'sponding to those beneath the same. Longitudinal beams 6262 are arranged parallel to' each other, and s aced above the roof and connected therewit 1 at thei: ends are vertical studs 6363. A beam 64 is arranged beneath each of the beams 52, and is formed integral with the roof 54 throughout its length. Suitable vertical studs 6565 conmeet the beams 62 with the beams 64, all of said vertical studs being in vertical alinement with corresponding studs 57, and the parts being connected together by vertical tie rods 66-66, as best seen in Fig. 20- Each of the beams 62 is connected with is corresponding beams 64 bv means of incline bra'ces 67-67, which are disposed between the "ertical studs 65 and connecting the lower end of one of the said studs with tl1e u)per end of the next contiguous stud. At the middle of the truss formed by the beams 62 and 64 and the connecting parts, the incline braces 67 are crossed, as indicated, for increasing the strength of the central portion of the truss while the remaining portion ofthe truss is n'efel'ably provided with single incline braces. Transverse beams 6-6S are spaced above the. roof 54, and are sup )orted on vertical studs 6969 at the IPIIC s. beneath each of the beams 6-5 is a corresponrh ing parallel beam 70 which L formed integral beams 68 and 70, of course. intersect the beams 62 and 64, and at the points of inter section the studs 65 connect said beams, the beams 68 and 70 being further connected by incline braces 7171, any fun her bracing members being employed according to the particular requirements'of the given caisscn.

As best seen in Fig. 20, each of the incline braces of all of the trusses is prodded with a stiffening rod or rods, and each of the vertical studs 57, which is not in alinement with the studs 65, is connected by a suitable tie Arranged throughout its length with the roof 54. The

rod-with the roof, the said tie rod extending from below the respectivm to a point erably prowided with a longitudinally ar-.

ranged stitfenin rod or bar, and, while one rod is shown as Htending-beyond theconcreme, of course as many rods, bars, or other metallic reinforcements may be used as are necessary, and they may be entirely embedded in the concrete if desired. The roof 5% in addition to being formed integral with the side walls, and also being connected therewith by the trusses within the working chamber, is further braced by lance-braces 72--72 s aced apart along the edges of the roof.

he trihedral angle formed at each side of each knee-brace by the juncture of the triangular knee-brace with the vertical wall,

and the horizontal roof, is formed with a filling 73 which aids in bracing the structure. The trihedral angle formed at each corner of the workin chamber by the juncture of the roof with the sides and ends of the casing is also provided with a filling 74.

As seen in Figs. 23, 24, 25 and 26 the trusses. may take various forms best ada ted for the particular caisson. In Fig. 23, have illustrated trusses 75-75, formed with upper and lower chords and suitable incline braces. I have also illustrated a transverse truss 7 6 in the working chamber consisting simply of up 3?! and lower chords and vertical studs. In ig. 24. I have shown the trusses 78 and 79 above the working chamber as formed of upper and lower chords connected by a continuous web, and I have also shown the transverse truss S0 in the working chamber as being formed of upper and lower chords connected by a continuous web. In Fig. 25, I have illustrated longitudinal trusses 81, and transverse trusses 82, as composed simply of upper and lower chords connected by vertical studs. I have also illustrated the trusses S3 and S4 in the working chamber as similarly constructed. In Fig. 26, I have shown the longitudinal trusses S5, and the transverse trusses 86, as being formed simply of solid integral webs. The longitudinal trusses S7, and transverse trusses S8, of the working chamber being similarly constructedj As indicated in Figs. 12 and 13, the )resent improved caisson is especially well adapted for use in forming the foundation for the subaqueous tunnel. A number of the caissons are sunk end to end, and after the same have arrived at the re uired elevation for forming a good, firm oundation, the working chamber is filled with concrete, as'at 50, as indicated in Fig. 13, and then the tunnei walls 51 are cast upon the caisson before the cotter-dam walls are removed.

It is to be noted that some of the trusses employed in some of the structures illus 'trated, include a portion of' the roof for-a completion of the truss, and, therefore, for

the )urpose of convenience, and for distinguis ing the elements referred to throughout the appended claims, I have referred to that port-ion of each truss which is not a part of the roof as a truss formation, and the term truss formation, I desire construed to cover any portion of any truss illustrated not included in the roof.

As is obvious from Fig. 20, as well as from numerous other figures of the drawing, the cofferdam trusses are superposed relative to the working chamber trusses so that the caisson structure may be properly said to be braced by tiers of superposed trusses, it being obvious that as many tiers of trusses may be employed as are found desirable according to the vertical dimensions of the caisson.

-What I claim is 1. In a caisson, the combination with vertical inclosing walls, and a roof cast integral therewith for forming a. working chamber, of a truss formation connected with the vertical walls and roof for transmitting strains.

2. In a caisson, the combination with inclosin walls of a truss extending across the space etween the walls, and having its ends cast integralwith the walls.

3. In a. caisson, the combination with vertical inclosing walls and a roof, of a truss formation arran ed within the inclosing walls, and connecte to the walls and roof.

4. In a caisson, the combination with vertical inc-losing walls, and a roof constituting a working chamber, of a truss chord connecting the vertical walls within the working chamber, and. truss braces connecting th chord with the roof.

5. In a caisson, the combination with inclosing vertical walls and a roof cast integral,

f a truss chord cast integral with the walls, and a. vertical stud cast integral with the chord and with the roof.

6. In a caisson the combination with vertical inclosing walls, and a roof cast integral, intersecting truss chords connecting said vertical walls, and vertical studs cast integral with the roof and with the chords, for connecting the chords to the roof.

7. In a caisson, the combination with vertical inclosin walls, and a horizontal roof cast integral t ierewith, of a plurality of kneebrace fillings disposed in the angle produced by-thc union of the vertical walls'and roof and fillings for the trihedral angles produce by the union of each knee-brace til ing with the vertical wall and roof.

8. In acaisson tical inclosing walls and a rooft'ormed inte ral therewith for producing a working chain er of bracing beams connecting the walls, and means connecting said beams with the roof said connecting means being formed integral with the bracing beams and with the roof.

. 9. In a caisson, the combination with vertical inclosing walls and a roof formed intethe combination with ver- 10. In a caisson, the combination with vertical inclosing walls and a roof cast of concrete of a concrete truss formation beneath and connected to said roof, a concrete truss formation above and connected to said roof, and means connecting the truss formations.

11. In a caisson, the combination with vertical inclosing walls, and a roof cast of concrete, intersecting brace beams spaced from said roof, and means formed integral with said beams and extending to and formed integral with the roof 1n connecting the beams to the roof.

12. In a caisson, the combination with inclosing walls, of a brace arranged beneath the said roof and connected to the inclosing walls, a vertical stud connecting the brace with the roof, bracing means arranged above the roof, :1 vertical stud connectin said last-mentioned bracing means with the roof in vertical alinement with the vertical stud of the first-- mentioned brace, and means extending longitudinally through both of said studs and through said brace and bracing means for securin the parts together.

I together.

13. n a caisson, the combination with the walls and roof of a working chamber, of intersecting bracing beams s aced from said roof on one side thereof, an bracin beams spaced from the roof on the other sirfe thereof, means connectin all of said bracing beams to the roof, and means for tying all of said bracing beams together.

14. In a caisson, the combination with inclosing walls and a roof reducing a working chamber, of a bracing li eam spaced on one side of the roof, means connecting said beam with the roof, a bracing beam arranged on the opposite side of the roof, means connecting last mentioned bracing beam to the roof, and a tie rod connecting said bracing beams 15. In a caisson, the combination with inclosing walls and a roof constituting a work ing chamber of intersecting bracing beams spaced on one side of said roof, vertical studs connecting the bracing beams at the point of intersection to the roof, a bracing beam disposed on the opposite side of said roof, a vertical beam with the roof in vertical al the rst-mcntioned stud, and tending through said studs and beams together.

6. Ina caisson, the combination with inclosing walls, and a roof constituting a working chamber, of a plurality of truss formations arranged on one side of the roof and formed integral therewith, and intersecting truss formations also formed integral with the roof.

inement with a tie rod exsecurmg said 17. In a caisson. the combination with in-' closing vertical walls and a roof cast integral, of'a beam s aced fromsaid roof, means cast integral wit I the beam at its end and connecting the same with the roof, and an intermediate brace cast integral with said beam and also formed integral with the roof.

18. In a caisson, the combination with vertical inclosed walls, and a roof constitutin a working chamber, the roof being formed with an aperture, of. an annular ring formed of right angle material, one of the angles of the ring being embodied in the material of the roof in position for having the opening of the ring registered with the aperture in the roof, 1e plate to the roof, a second plate connected with the first-mom tioned plate, and a hollow shaft connected with the second-mentioned plate.

19. In a caisson, the combination with inclosing walls and a roof constituting a working chamber, of intersecting bracing beams spaced from said I vertical studs arranged at the points of interbeams for connecting 9 the bracing beams to the roof, :1 bracing beam spaced from the opposlte side of said roof,

d a vertical stud connecting the last-mentioned beam with the roof.

20 In a caisson, the combination with a workin chamber cast of concrete, of a'pluralityo? trusses arranged withinsaid working chamber and cast integral with the walls thereof.

21. In a caisson, the combination with a 1 working chamber cast of concrete, and intersecting trusses arranged within said workin chamber and cast integral with the walls thereof. l

22. In a caLsson, the combination with a working chamber, of trusses arran ed therein and cast integral with the side wal s and roof thereof.

23. In a caisson, the combination with a working chamber cast of concrete, and a truss 1 cast within said working chamber integral with the roof and side walls thereof, and tie and engaging the truss transmitting strains.

24. In a caisson the combination with a 1 rectangular casin and a roof therefor, of a filling of trihedra form for each of the corners produced by the union of the walls of the casing with the roof.

25. In a caisson, the combination with an 1 inclosed concrete casing, of tiers of superposed trusses formed integral with said casmg.

26. In a caisson the combination with a. casing formed of walls bearing angular rela- 1 tion to each other and a roof therefor, of a filling for each corner roduced by the junctureof two of the wa is of the caisson withthe roof. i

27. In a. caisson, the combination with an inelosing' casing, a brace extendin across the I inclosurc and formed integral with the walls of the casing, and knee braces at the ends of said braces and formed integral therewith and with said walls.

28. In a caisson, the combination with an inclosing casing, and a roof connecting the walls thereof and spaced aboxe the lower end of said walls for forming a working chamber, of a brace extendin across said working chamber and formed integral at its ends with the walls of said casing, and a knee brace at each end of said brace formed integral therewith and with the respective walls of the casing.

29. In a caison, the combination with an inclosing easing, a roof therefor, a brace connecting the walls of said casin above said roof and formed integral with said walls, and a knee brace at each end of said brace and formed inte ral therewith and with the respective wall s of the casing.

30. In a caisson, the combination with an inclosing casing and 0. rec therefor, of a brace extending across thei closure of said said walls and connected at its ends to the l walls and connected at its edge to the roof, and a truss arranged at right angles to the first mentioned truss and connected to the.

roof. 4

32. In a caisson, the combination with inclosing walls and a roof therefor, of a truss arranged within the inclosure produced by said inc-losing walls and disposed for strengthening the roof, and a truss arranged at ri ht angles to the first mentioned truss and a so dis )osed for stren thening the roof.

n testimony whereof I- affix my signature in presence of two witnesses.

OLIVER CROMWELL EDWARDS, Ill. Witnesses:

HENRY Comm,

D. W. CHAMBERLIN. 

